Light source and a manufacturing method therewith

ABSTRACT

A method of forming a device includes emitting a coherent light beam and providing a mask including a region transparent to the light beam. The method further includes projecting the light beam on a photosensitive layer through the transparent region of the mask. The method further includes forming a recess in the photosensitive layer, wherein the recess corresponds to a position of the transparent region of the mask. The method further includes filling an organic light emitting material in the recess.

CROSS-REFERENCE To RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 15/703,580, filed Sep. 13, 2017. The entiredisclosure of each of the above-described patent applications isincorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a coherent light source designed formultiple purposes.

BACKGROUND

Light source can be used in various fields. Laser is one of the lightsources been used in different industries. Lasers are distinguished fromother light sources by their coherence. Spatial coherence is typicallyexpressed through the output being a small beam, which isdiffraction-limited. Laser beams can be focused to very tiny spots,achieving a very high irradiance, or they can have very low divergencein order to concentrate their power at a great distance.

SUMMARY

A method of forming a device includes emitting a coherent light beam andproviding a mask including a region transparent to the light beam. Themethod further includes projecting the light beam on a photosensitivelayer through the transparent region of the mask. The method furtherincludes forming a recess in the photosensitive layer, wherein therecess corresponds to a position of the transparent region of the mask.The method further includes filling an organic light emitting materialin the recess.

In some embodiments, the mask is a 1:1 mask and a phase differencewithin the light beam is less than about 1 m. In some embodiments,forming a recess in the photosensitive layer further comprising directlycarving out a portion of the photosensitive layer by the light beam.

In some embodiments, the photosensitive layer is a stack including atleast two different types of photo sensitive films, and projecting thelight beam on a photosensitive layer through the transparent region ofthe mask is dependent on a type of the photosensitive layer.

In some embodiments, emitting a light beam further comprises providing alight source, wherein the light source is configured to be able to emitlight beams having at least two different wavelength.

In some embodiments, the method further comprises scanning the maskprior projecting the light beam on a photosensitive layer through thetransparent region of the mask.

A method of forming a device includes generating a coherent light beamfrom a light source and detecting a type of a first film by the lightsource. The method also includes electively annealing the first film bythe coherent light beam in accordance with the type of the film.

In some embodiments, a phase difference within the light beam is lessthan about 1 m. In some embodiments, the method includes splitting thecoherent light beam into a plurality of light beams prior to selectivelyannealing the first film.

In some embodiments, the method further comprises a second film underthe first film, wherein the second film is transparent to the coherentlight beam. In some embodiments, the method further comprises a secondfilm adjacent the first film, wherein the second film is transparent tothe coherent light beam. In some embodiments, the method furthercomprises moving he first film in relative to the light source.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a method of manufacturing a device.

FIG. 2 illustrates an operation of the method in FIG. 1.

FIG. 3A-3C illustrate a photolithography process.

FIG. 4A-4B illustrate a photolithography process.

FIG. 5A-5D illustrate a photolithography process.

FIG. 6A-6D illustrate an annealing process.

FIG. 7 illustrates a light source.

FIG. 8A-8C illustrate some examples of a light emitting apparatus.

FIG. 9A-9F illustrate some examples of a photolithography process.

DETAILED DESCRIPTION OF THE DISCLOSURE

The present disclosure provides a method and an apparatus to performphotolithogrphy process by using a cohenerent light source. The presentdisclosure also uses a 1:1 mask and no lease (curvature tense) needed.

The present disclosure is to provide a new design of an electrode for anorganic light emitting material used in a flexible panel. The electrodehas a suitable dimension is order to minimize the reflection of theambient light. Material of the electrode also has a high flexibility andlow resistivity so as to make the flexible panel foldable and low powerconsumption. Through the present disclosure, a flat panel designer canhave a much greater window to allocate the driving circuit, touch panelwires within the light emitting pixel array.

[Photolithography]

FIG. 1 illustrates an embodiment of an apparatus designed for aphotolithography process. The apparatus has a light source 100 to emit alight beam 110. The light beam 110 can project to a photo sensitivelayer 300, which is disposed on a substrate 400 during thephotolithography process. Photo mask 200 can be placed between the lightsource 100 and the photo sensitive layer 300.

A distance H is measured from a surface 200 a of the photo mask 200 to asurface 302 of the photo sensitive layer 300. Surface 200 a faces thephoto sensitive layer 300 and surface 302 faces toward the photo mask200. The distance H can be zero in some embodiments, i.e. the photo mask200 is in touch with the photo sensitive layer 300.

Light beam 110 has a wavelength between about 300 nm and 450 nm. In someembodiments, the wave length is between about 350 nm and 390 nm. In someembodiments, the light beam 110 is more coherent than an i-line. Phasedifference within the light beam is less than about 1 m. In someembodiments, the light beam is a laser. In some embodiments, the lightbeam is a NdYAG laser.

The photo mask 200 is made with a material that can block the light beam110 to pass though the photo mask 200. The light beam 110 can reach thephoto sensitive layer 300 via the through hole or transparent region 210in the photo mask 210. The photo mask 200 may have several through holeswith different shapes or sizes as shown in FIG. 1. The pattern ofthrough holes of the photo mask can be projected to the photo sensitivelayer 300 by the light beam 110.

Photo sensitive layer 300 can be AZ9260, AZ4562, AZ6632, AZ1518,AZ1512HS, AZ701 MR, AZ5214E, or other suitable photoresist (PR). In someembodiments, a portion 306 of the photo sensitive layer 300 is exposedto light beam 110 and vaporized by the light beam 110. When the lightbeam 110 projects on the photo sensitive layer 300 via the through hole210, molecules in the portion 306 absorb the energy of the light beam110 and then transform from a solid state to a gas state. Materialfilled in the portion 306 is removed and a hole or recess is formed inthe photo sensitive layer 300 after exposed to light beam 110. In someembodiments, an organic light emitting material is filled into the holeor recess.

In some embodiments, the light beam 110 may change property, such asbonding (or cross linking), of the photo sensitive layer 300. Theportion 306 after exposed to the light beam 110 may still stay in solidstate but can be developed by a developer and transformed into a recessor a hole in the photo sensitive layer 300. In some embodiments, anorganic light emitting material is tilled into the hole or recess.

In some embodiments, the size of beam 110 is about 1 mm² or less. Insome embodiments, if the size of hole 210 is smaller than the beam size,a one-shot exposure operation can cover the whole area of the hole 210.The whole area of the portion 306 receives the energy from the beam 110in a same shot. If the size of hole 210 is greater than the beam size, amultiple-shot operation is needed to cover the whole area of the hole210. The whole area of the portion 306 receives the energy from the beam110 in multiple shots.

To perform a multiple-shot operation, there is a relative movementbetween the substrate 400 and the light source 100 (or light beam 110).In some embodiments, the substrate 400 is located on a movable stage.The stage is engaged with a drying system such as a step motor, magnetictrail, etc. When a multiple-shot operation is needed, the stage is movedin relative to the light beam 110 by the driving system. In someembodiments, the light source 100 is engaged with a drying system suchas step motor, magnetic trail, etc. When a multiple-shot operation isneeded, the light source 100 is moved in relative to the stage by thedriving system. In some embodiments, a multiple-shot operation isperformed though an aid of a shutter system.

FIG. 2 is a cross sectional view of a photolithogray operation accordingto the present disclosure. In photo mask 200, the dotted lines representregions that are transparent to the light beam 110 and solid linesrepresent regions that are not transparent to the light beam 110 (i.e.blocking region). In the subject example, the size of the light beam 110is equal or greater than the size of the dotted line regions. However,this should not be deemed as a limitation.

Direct carving is used in the subject example, however, indirect carvingis also suitable. As in FIG. 2, a portion of photo sensitive layer 300under the dotted line region is directly carved by the passing lightbeam 110. The light beam 110 projects a 1:1 pattern from photo mask 200to the photo sensitive layer 300. Since the size of the light beam 110is equal or greater than the size of the dotted line regions. Alignmentbetween the light source and the photo mask 200 can be performed to makesure the emitted light beam 110 is aligned with the dotted line region210 prior to the exposure.

Furthermore, a continuous exposure mode is also adopted in the presentdisclosure. In FIG. 3A, the light source is moving toward the right sideof the drawing in relative to the stage 400 and photo mask 200. At timet₁, a portion of light beam 110 is blocked by the solid line region ofthe photo mask 200, and a portion of light beam 110 passes the dottedline region 210 of the photo mask 200. A portion of the photo sensitivelayer 300 is carved out by the passed light beam 110 and formed athrough hole in the photo sensitive layer 300.

The relative motion between stage 400/photo mask 200 and the light beamcontinues. In FIG. 3B, at time t₂, there is still a portion of lightbeam 110 being blocked by the solid line region of the photo mask 200,and a portion of light beam 110 passed the dotted line region 210 of thephoto mask 200. A further portion of the photo sensitive layer 300 iscarved out by the passed light beam 110 and formed a through hole in thephoto sensitive layer 300. The though hole in the photo sensitive layer300 is enlarged.

The relative motion between stage 400/photo mask 200 and the light beamcontinues. When at time t₃, as shown in FIG. 3C, the dotted line region210 is fully covered by the light beam 110. The shape and size (width,or 2-dimensional size) of the dotted line region 210 is 1:1 projected tothe photo sensitive layer 300 and formed a through hole in the photosensitive layer 300.

Light beam emitting can be controlled in various ways. As in FIG. 4A,the light source 100 has a detector 105. The detector 105 emits acousticwave or optical beam 106 toward the photo mask 200. When the acousticwave or optical beam 106 reaches the photo mask 200, the detector 105can recognize the surface condition of the photo mask 200 (for example,through reflected acoustic wave or optical beam) and further identifieswhere the dotted line region 210 is. The acoustic wave or optical beam106 used by the detector 105 does not damage or change any property ofthe photo sensitive layer 300.

Once the dotted line region 210 is identified, an instruction from acontrol unit (can be external or embedded in the light source 100) issent to the light source 100 to determine when and where to emit thelight beam 110 through exit 107. As shown in FIG. 4B, when the exit 107is priximal or over the dotted line region 210, light beam 110 isemitted from the exit 107 and start projecting pattern of the dottedline region 210 to the photo sensitive layer 300.

With the detector 105, the light beam 110 can be selectively turned onand off by the light source 100. For some embodiments, the light beam110 is only turned on when the exit 107 is over the dotted line region210. The possibility for the light beam 110 to hit the solid line regionof the mask 200 can be reduced.

FIG. 5A-5D illustrate an embodiment performing a multi-layerphotolithography operation. In the drawings, there are only twophotosensitive layers 300 a and 300 b stacked over the substrate 400.However, the same concept can apply to more than two photosensitivelayers. In some embodiments, photosensitive layers 300 a has a highestpeak absorption coefficient a to a cohesive light beam with a wavelengtharound λ₁. Photosensitive layers 300 b has a highest peak absorptioncoefficient α₂ to a cohesive light beam with a wavelength around λ₂.

For mask 200, there are two different dotted regions, 210 a and 210 b.In some embodiments, dotted region 210 a is transparent to light beamwith a wavelength around λ₁, and non-transparent to light beam with awavelength around λ₂. Dotted region 210 b is transparent to light beamwith a wavelength around λ₂, and non-transparent to light beam with awavelength around λ₁. In some embodiments, dotted region 210 a istransparent to light beam with a wavelength around λ₁, and alsotransparent to light beam with a wavelength around λ₂. Dotted region 210b is transparent to light beam with a wavelength around λ₁, and alsotransparent to light beam with a wavelength around λ₂.

FIG. 5B illustrates a selective photolithography operation with directcarving. Light beam 110 a is selected to pass through dotted region 210a. Photoresistive layer 300 b has a low absorption coefficient β₂ tolight beam 110 a in comparison to photoresistive layer 300 a. In someembodiments, β₂ is considered as 0 in comparison to α₁. In other words,photoresistive layer 300 b is transparent to light beam 110 a. A hole orrecess is formed only in photoresistive layer 300 a by light beam 110 a.

FIG. 5C illustrates another selective photolithography operation withdirect carving. Light beam 110 b is selected to pass through dottedregion, 210 b. Photoresistive layer 300 a has a low absorptioncoefficient β₁ to light beam 110 b in comparison to photoresistive layer300 b. In some embodiments, β₁ is considered as 0 in comparison to α₂.In other words, photoresistive layer 300 a is transparent to light beam110 b. A hole or recess is formed only in photoresistive, layer 300 b bylight beam 110 b.

FIG. 5D illustrates another structure after a selective photolithographyoperation with direct carving. Photoresist layer 300 a has severalrecesses or through holes formed by the selective photolithographyoperation. Photoresist layer 300 b also has several recesses or throughholes formed by the selective photolithography operation. Some recessesor holes may align with recesses or holes in photoresist layer 300 a mayalign with recesses or holes in photoresist layer 300 b to form a recessor through hole like trench 306 a. Some recesses or holes recesses orholes in photoresist layer 300 a may be partially overlapped withrecesses or holes in photoresist layer 300 b to form a recess or throughhole like trench 306 b.

[Annealing]

Light source 100 in FIG. 1 can be also adopted in an annealingoperation. Similar to the photolithography operations described above,the energy of light beam is used to provide energy to anneal film 500 inFIG. 6A. Light beam 120 is emitted from light source 100 and projectedon film 500. Light beam 120 may provide heat to film 500 and change themicro structure or bonding condition inside film 500.

FIG. 6B illustrates a selective annealing operation performed by thelight source 100. In some embodiments, regarding to the light beam 120,the thermal absorption coefficient of 500 b is almost zero comparing tothe thermal absorption coefficient of 500 a. Therefore, when light beam120 is emitted from the light source 100 and toward the substrate 400,film 500 b is transparent to the light beam 500 b. Energy carried bylight beam 120 is absorbed by film 500 a. Only film 500 a is annealed bythe light beam 120.

In FIG. 6C, a detector 405 is used to detect the film type. When thelight source 100 is moving in relative to the substrate 400. Detector405 is configured as an inspector for detecting which type the film is.For example, detector 405 can detect there are two different types offilms, 500 a and 500 b, disposed over the substrate 400. The informationof film type is sent to a processing unit. The processing unit instructsthe light source to emit a light beam with a desired wavelength forselective annealing.

For example, when detector 405 is scanning a top surface of filmsdisposed over substrate 400, information of the areas and locations offilm 500 a and 500 b are generated by the processing unit via thescanning result performed by the detector 405. If only film 500 a needsto be annealed, the processing unit sends an instruction to the lightsource 100 to emit suitable a light beam through exit 107 when the exit107 passes over the area covered by film 500 a.

In some embodiments, when detector 405 is scanning a top surface offilms disposed over substrate 400, information of the areas andlocations of film 500 a and 500 b are generated by the processing unitvia the scanning result performed by the detector 405. If only film 500a needs to be annealed, the processing unit sends an instruction to thelight source 100 to emit a suitable light beam with a first wavelengththrough exit 107 when the exit 107 passes over the area covered by film500 a. If only film 500 b needs to be annealed, the processing unitsends an instruction to the light source 100 to emit a suitable lightbeam with a first wavelength through exit 107 when the exit 107 passesover the area covered by film 500 b.

FIG. 6D is a cross sectional view of a photolithogray operationaccording to the present disclosure. A mask 600, similar to the photomask 200 in FIG. 3A, is adopted for a selective annealing operation. Thedotted lines represent regions 610 that are transparent to the lightbeam 120 and solid lines represent regions that are not transparent tothe light beam 120 (i.e. blocking region). In the subject example, thesize of the light beam 120 is equal or greater than the size of thedotted line regions. However, this should not be deemed as a limitation.

As in FIG. 6D, a portion of film 500 b under the dotted line region 610is directly annealed by the passing light beam 120. A portion of film500 b under the solid line region is not annealed because the solid lineregion of mask 600 blocks the light beam 120. In some embodiments, thefilm is crystallized or re-crystallized by the annealing operation.

[Light Source Configuration]

FIG. 7 illustrates an embodiment of a light source 100 having severalexits 107 for emitting light. Light source 100 can emit multiple lightbeams in a simultaneous manner.

FIG. 8A illustrates an embodiment of a light source 100 configured toemit multiple light beams. The light source has a light generator 102for generating a light beam 104. The light beam 104 emits into asplitter 103. The splitter 103 can split the light beam 104 into severaldifferent light beams 110 in a same direction. In some embodiments, thelight beams 110 can be directed to at least two different directions.

In some embodiments, the light source 100 has at least two lightgenerators 104 a and 104 b. Light generator 104 a generates a light beam110 a with a wavelength of λ₁ and light generator 104 b generates alight beam 110 b with a wavelength of λ₂, wherein λ₁ is different fromλ₂. Light beam 104 a is splitted by the splitter 103 into several lightbeams 110 a with a wavelength of λ₁. Light beam 104 b is splitted by thesplitter 103 into several light beams 110 b with a wavelength of λ₂.

The splitter 103 can be configured to emit the light beam in any patternas the user desire. For example, in FIG. 8C, the light source 100 hastwo light generators 104 a and 104 b. Light generator 104 a generates alight beam 110 a with a wavelength of λ₁ and light generator 104 bgenerates a light beam 110 b with a wavelength of λ₂. The splitter 103can arrange the light emitting two different light beams, 110 a and 110b, in an alternating manner. Therefore, a light beam 110 a withwavelength of λ₁ is neighbored with a light beam 110 b with wavelengthof λ₂. In some embodiments, the splitter 103 can arrange the splittedemitted lights into a line or a two dimensional (2D) pattern.

FIG. 9A-9F illustrate an operation of using the multiple light beam toperform photolithography. Direct carving is used for illustration, butsame operation can also apply to an indirect carving operation. In 9A, amulti-beam light source 100 is moving to the right side in relative tothe substrate 400. A photosensitive film 300 is over the substrate 400.

In FIG. 9B, when a light beam 110 is over the dotted region 210 of themask 200, the light beam 110 passed through the mask 200 and provides afirst shot to the photosensitive film 300. A recess 306 a is formed inthe photosensitive film 300. A depth of the recess 306 a is shallowerthan the whole thickness of the photosensitive film 300.

In FIG. 9C, while the light source 100 continues travelling towardright, the photosensitive film 300 receives more and more shots throughthe dotted region. The recess 306 is enlarged by multiple shots lightbeam through the dotted region 210. As in FIG. 9C, the bottom of recess306 may be in a stepped shape. In some embodiments, the bottom surfaceof recess 306 may be in a curved shape, wherein a greatest depth is onthe left side and a smallest depth is on the right side.

As the operation progresses, the recess 306 a is changed to a throughhole in the photosensitive film 300 as shown in FIG. 9D. In someembodiments, when the recess 306 a becomes a through hole in thephotosensitive film 300. A detector as the detector 105 in FIG. 4A candetects the carving operation is completed. The signal will be processedby a processing unit. The processing unit instructs to turn off some ofthe light beams as in FIG. 9E.

When the light source start approaching next dotted region of the mask200. Some light beams are turned on again as in FIG. 9F to start acarving operation. Through the multi light beam light source, amulti-shot photolithography operation can be performed. Thephotolithography is by providing a certain amount of energy dosage to adesired area through a light beam. In some embodiments, a though hole inthe photosensitive film 300 is formed by multiple independent lightbeams and each independent light beam provides the certain amount ofenergy dosage to the desired area of photosensitive film 300.

In some embodiments, the multi-shot photolithography operation isperformed by a light source emitting multiple light beams having atleast two different light wavelengths. Therefore, a selectivephotolithography operation as described in FIG. 5A through FIG. 5D withmulti-shot photolithography is performed.

In some embodiments, the multi-shot photolithography operation isperformed by a light source emitting multiple light beams having atleast two different light wavelengths. Therefore, a selective threedimensional photolithography operation as described in FIG. 5D withmulti-shot photolithography is performed.

In some embodiments, the multi-shot annealing operation is performed bya light source emitting multiple light beams having at least twodifferent light wavelengths. Therefore, a selective annealing operationas described in FIG. 6A through FIG. 6D with multi-shot annealing isperformed.

The foregoing outlines features of several embodiments so that personshaving ordinary skill in the art may better understand the aspects ofthe present disclosure. Persons having ordinary skill in the art shouldappreciate that they may readily use the present disclosure as a basisfor designing or modifying other devices or circuits for carrying outthe same purposes or achieving the same advantages of the embodimentsintroduced therein. Persons having ordinary skill in the art should alsorealize that such equivalent constructions do not depart from the spiritand scope of the present disclosure, and that they may make variouschanges, substitutions and alternations herein without departing fromthe spirit and scope of the present disclosure.

1. An apparatus for photolithography, comprising: a light source foremitting a coherent light beam, wherein the coherent light beam isconfigured to be transparent to a region of a mask and projecting on apredetermined photosensitive layer for directly carving out theprojected portion of the photosensitive layer; and a stage for holding asubstrate having the photosensitive layer.
 2. The apparatus of claim 1,further comprising a driving system engaged with the stage to provide arelative motion between the light source and the substrate.
 3. Theapparatus of claim 1, further comprising a shutter system associatedwith the light source for performing a multi-shot carving on thephotosensitive layer.
 4. The apparatus of claim 1, further comprising adetector for emitting an acoustic wave or optical beam toward the mask.5. The apparatus of claim 4, wherein detector is designed to recognizethe surface condition of the mask.
 6. The apparatus of claim 4, whereindetector is selectively turned on or off by the light source.
 7. Theapparatus of claim 1, further comprising a control unit for sending aninstruction to the light source to determine when and where to emit thecoherent light beam through an exit on the light source.
 8. Theapparatus of claim 1, wherein the light source comprises at least twolight generators for emitting two different wavelength light beams. 9.The apparatus of claim 1, further comprising a splitter to split thelight beam from the light source.
 10. The method of claim 1, furthercomprising scanning the mask prior projecting the light beam on aphotosensitive layer through the transparent region of the mask.
 11. Anapparatus for annealing, comprising: a light source for emitting acoherent light beam, wherein the coherent light beam is configured toprovide energy to a film on a substrate; and a stage for holding asubstrate having the photosensitive layer.
 12. The apparatus of claim11, further comprising a driving system engaged with the stage toprovide a relative motion between the light source and the substrate.13. The apparatus of claim 11, further comprising a shutter systemassociated with the light source for perfuming a multi-shot annealing onthe film.
 14. The apparatus of claim 11, further comprising a detectorfor emitting an acoustic wave or optical beam toward the film.
 15. Theapparatus of claim 14, wherein detector is designed to recognize thetype of the film.
 16. The apparatus of claim 14, wherein detector isselectively turned on or off by the light source.
 17. The apparatus ofclaim 11, further comprising a control unit for sending an instructionto the light source to determine when and where to emit the coherentlight beam through an exit on the light source.
 18. The apparatus ofclaim 11, wherein the light source comprises at least two lightgenerators for emitting two different wavelength light beams.
 19. Theapparatus of claim 11, further comprising a splitter to split the lightbeam from the light source.